Progress in nonpolar and semipolar GaN materials and devices

Devices grown on c-plane GaN suffer from large internal electric fields due to discontinuities in spontaneous and piezoelectric polarization effects which cause charge separation between holes and electrons in quantum wells and limits the radiative recombination efficiency. Nonpolar GaN devices, such as in the m-plane (1100), are free from polarization related electric fields since the polar c-axis is parallel to any heterointerfaces. Semipolar GaN-based devices have reduced electric fields and in some cases, such as (1122), show a high propensity for Indium update for InGaN quantum wells.